Men work in an assay office, probably in Colorado. Shows an assayer pouring ore into a cupel over a stove. Shows barrels, sacks, sifters, tins, mortars and pestles, tongs, and graduated sizes of cupels in the laboratory.

Accession number: 86.200.2451; Attribution to Jackson based on the photonegative's inclusion in the History Colorado William Henry Jackson Collection.; History Colorado.; Condition: Scratched, developing flaws, masked, retouched, silvered.; Formerly Jackson 4284.; Handwritten on envelope: "Assaying, cupelling (Colo. Midland Ry.)."; Label on negative reads: "Detroit Publishing Co."; Original title and attribution on negative have been retouched and are illegible.; Title and: "04284" inked on negative.; Typeset title on negative reads: "04284" and "Assaying and cupeling."; R7201027269